Contemporary electronic circuits require carefully designed transmission paths to preserve signal integrity and minimize interference from foreign sources. One contemporary connector system, disclosed in U.S. Pat. No. 4,451,107, utilizes die cast zinc housings to provide grounding and EMI shielding. Another comtemporary connector system, disclosed in U.S. Pat. No. 4,655,518, employs ground contacts located on the outside of and parallel to columns of signal contacts to provide short ground paths and thereby promote signal integrity.
As switching speeds become even higher, signal integrity becomes more critical and the maintenance thereof must include provisions for the following: (a) low inductance signal return conductors to control common impedance noise generation; (b) a strong coupling of the signal conductors to their return conductors electrostatically and electromagnetically in relation to the coupling between proximate signal conductors in order to control crosstalk; and (c) a coupling relationship between signal conductors and signal return conductors which provides an impedance which matches the impedance of the source and load circuits in order to minimize signal reflections.
It is now proposed to provide in connectors and connector systems a low inductance (at high frequencies) signal return path in the form of a reference conductor (plate) between rows of signal conductors. Such a conductor, which is the form of a plate, will provide the essential element required in maintaining the signal integrity discussed above.